Acute Imidacloprid Exposure Alters Mitochondrial Function in Bumblebee Flight Muscle and Brain

Area of Science:

• Mitochondrial physiology and toxicology
• Insect neurobiology and behavior
• Environmental science and ecotoxicology

Background:

• Mitochondria are vital for cellular energy (ATP) production, essential for high-demand activities like bee flight and brain function.
• Neonicotinoids, widely used insecticides, are suspected of causing mitochondrial dysfunction in bees, impacting cognition and flight, though mechanisms remain unclear.
• Understanding these effects is crucial for pollinator health and sustainable agriculture.

Purpose of the Study:

• To investigate the effects of the neonicotinoid imidacloprid on mitochondrial oxidative phosphorylation in the brain and flight muscle of bumblebees (Bombus terrestris).
• To explore potential mechanisms by which imidacloprid may impair mitochondrial function and affect bee physiology.

Main Methods:

• High-resolution respirometry was employed to measure oxygen consumption and electron transport capacity in isolated mitochondria.
• Experiments focused on the flight muscle and brain tissues of worker bumblebees.
• Acute exposure protocols were used to assess immediate effects of imidacloprid.

Main Results:

• Acute imidacloprid exposure significantly increased routine oxygen consumption in bumblebee flight muscle mitochondria.
• A trend towards increased overall oxygen consumption and a significant increase in maximum electron transport capacity were observed in brain mitochondria.
• High intra-individual variability in brain tissue limited conclusive findings on imidacloprid's effects on brain mitochondria.

Conclusions:

• Imidacloprid exposure affects mitochondrial respiration in a tissue-specific manner in bumblebees.
• Increased oxygen consumption in flight muscle may explain observed declines in bee flight activity.
• Further research is needed to fully elucidate the impact of neonicotinoids on bee brain mitochondria and overall health.